[These days, many games feature a blend of action and RPG elements -- is there any way to determine whether a blend is effective? Is there any way to think about the specific target you're aiming for? Game design analyst Josh Bycer takes a stab at it.]

One of the key areas of evolution in game design has to be the merging of genres. Games like the Uncharted series combine shooting, puzzle, and adventure elements together.

Besides expanding the gameplay, this serves another purpose; it opens up the game to more people.

Two genres that have been working the hardest to do this would be action games and RPGs. The determining factor is the abstraction of skill and how each game handles it differently. This has lead to the term "skill abstraction." It's defined as:

The degree of which player skill (or input) has an effect on the gameplay.

In their infancy, both genres existed on complete opposite ends of the spectrum. Slowly, over the years, games designed for both genres have been moving inward. Action games have been adding more RPG elements; RPGs have become more action oriented.

On one hand, this has opened up the respective genres to more gamers. However, to quote Abraham Lincoln, "...you can't please all the people, all the time."

Before we examine this, here is a chart showing this abstraction:

-100 percent refers to games with zero abstraction of skill. These are games where player skill is the only determining factor in beating the game. For instance, early shooters didn't deal with the concept of in-game accuracy; if your cursor was on the enemy, you were going to hit them. Gun games, popularized in the arcade scene, are another great example. How well the player can aim the gun and prioritize threats were the only factors that separated victory from defeat.

-75 percent brings us to modern day shooters, where factors like the characters accuracy and movement now play a role. You can't expect your character to fire well while running and jumping, this also gave rise to the importance of cover. Skill is still important, but now the player must balance their skill with the additional factors of the character.

-50 percent is where all guns are not created equal. Games like Stalker, Call of Duty, and even Team Fortress 2 feature a variety of weapons. In Stalker, there are multiple pistols, shotguns, and assault rifles, but they are not only differentiated by type. Guns vary in terms of how much damage they do, their accuracy, and so on. Even though the player may be a crack shot, if their gun has poor accuracy, they may not be able to hit enemies or do enough damage to kill them.

Team Fortress 2 has embraced this concept, with all kinds of equipment available. Different guns for the classes have different effects, and give the player more options on their classes' load-out.

-25 percent has been recently popularized thanks to Borderlands. Billed as a "role playing shooter," the game features the same kind of weapon diversity seen in games at the -50 percent mark. Combat is still twitch-based, and getting a hit on the weak spot of an enemy will cause more damage. The key difference is that now the player has their own experience level to contend with.

The leveling system works like this: if both the player and enemy are the same level, then there are no modifiers done to damage on either side. If the player is a higher level, they will receive a damage bonus based on the difference in levels, and the enemy will receive a damage penalty when attacking the player. The effects are reversed if the player is a lower level compared to the enemy.